Means for constant pressurization of inflatable and other enclosures



J. P. KWAKE 3,478,472 MEANS FOR CONSTANT PRESSURIZATION OF INFLATABLE Nov. 18, 1969 AND OTHER ENCLOSURES Filed NOV. 29; 1967 United States Patent 3,478,472 MEANS FOR CONSTANT PRESSURIZATION OF INFLATABLE AND OTHER ENCLOSURES John P. Kwake, 2507 Carob Drive, Los Angeles, Calif. 90046 Filed Nov. 29, 1967, Ser. No. 686,528 Int. Cl. E04b 1/345; E04b 9/00 US. Cl. 52-1 9 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to pressurized enclosures and more particularly, to methods and means for pressurizing inflatable enclosures.

Because inflatable enclosures are generally not made air-tight, air escapes slowly but continuously through leaks in the enclosure and intermittently but relatively rapidly when doors in such enclosures are opened. Therefore, provision must be made for flowing air into inflatable enclosures to make up for these losses. Heretofore, air has been passed into inflatable enclosures by using a blower, a switch means for stopping and starting the blower, and a. control means for transmitting changes in the internal pressure to the switch means which either turned off or turned on the blower. Examples of such devices are de scribed in Turner Patent Number 2,948,286, issued August 1960, and in John P. Kwake application Serial No. 458,- 609 entitled Inflatable Structure, now abandoned.

The predominant characteristic of most presently-used pressurizing methods is that they operate intermittently, that is, the blower blows either no air into the inflatable enclosure or it blows air at its full capacity into the enclosure. When the blower is not in operation, the walls of the inflatable enclosure can sag slightly as air leaks out of the enclosure. During part of this period, then, the walls are not firmly supported by internal air pressure. If atmospheric conditions are calm, the blower will ultimately commence operation to raise the inflatable enclosure back to its normal position without damage to the enclosure. However, if a strong wind rises at this time, tearing of the inflatable enclosure may occur due to flapping of the walls of the enclosure.

When a door is opened in an inflatable enclosure there is often a rapid decrease in internal air pressure. The presently-available pressurizing devices with their otf-o'n operation are not able to react quickly to such rapid changes. That is, there is a time lag before the blower can elfectively begin to restore air pressure to normal. During this period tearing of the enclosure fabric may also occur.

One method of overcoming the problems associated with off-on methods of inflating air-supported enclosures is also shown by the aforementioned Turner patent. Such method involves continuously passing air into an airsupported enclosure at the rate which is preset, constant and approximates the normal rate of air loss due to leakage from the enclosure. To maintain the enclosure in its normally inflated position when air is lost other than by leakage, for example, when a door is opened, a second blower is employed to pass air into the enclosure only at such times. This method is disadvantageous because of its relatively large equipment requirement since two parallel "ice blower assemblages are required and because the continuously operating blower has to be readjusted as the leak rate changes.

SUMMARY The herein-described invention employs a control means which senses changes in the internal pressure of inflatable enclosures and transmits such changes to a partially retractable air conduit which accepts varying proportions of the air exhausted by a blower, which operates continuously, in response to the internal air pressure. Because the blower continuously exhausts at least some air into the inflatable enclosure, the enclosure remains firmly supported by the internal air pressure. Even when a door is opened and the internal air pressure decreases rapidly, the continuously-operating device of this invention is able to restore the internal air pressure to normal before any damage can be caused to the enclosure by, for example, strong winds.

DESCRIPTION OF THE DRAWINGS FIGURE 1 is a perspective view of an inflatable enclosure in inflated position over a swimming pool together with the continuous inflating means of this invention.

FIGURE 2 is a sectional view taken along the line 2-2 of FIGURE 1 showing the arrangement of the component parts of the inflating means of this invention and showing the inflating means in both open and closed positions.

FIGURE 3 is an end sectional view taken in the direction 3 of FIGURE 2 showing the air flow pattern from the inflating means of this invention into the inflatable enclosure.

FIGURE 4 is an exploded view showing the means associating the air conduit (without cover material) to the blower of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In general, this invention comprises a method and means for continuously blowing air into an inflatable enclosure in response to the air pressure within the inflatable enclosure to thereby provide a substantially constant pressure within the inflatable enclosure. More particularly, this invention comprises, in combination, a blower which is continuously on, a partially collapsible or retractable air conduit positioned to pass from the blower into an enclosure, and a control means which alters the amount of air accepted from the blower by the air conduit in response to changes in the air pressure within the inflatable enclosure. Because the forced air means of this invention is sensitive to the air pressure within an inflatable enclosure and because such means employs a continuously operating blower, the amount of air entering the inflatable enclosure is varied so that a substantially constant air pressure is maintained in the inflatable enclosure. The substantially constant internal air pressure improves the stability of inflatable enclosures in high winds and prevents tears from developing in the inflatable enclosure fabric due to such high winds.

This invention will be further described with reference to the drawings. In FIGURE 1, the numeral 10 designates an inflatable enclosure in the fully inflated position over a swimming pool 11. The inflatable enclosure 10 comprises a cover 12 and a circumferential tube 13 depending therefrom and resting on the pool area decking 14, The cover 12, in turn, consists of a roof section 15 and a wall section 16 having a door 27 located therein. The roof 15 and wall 16 sections may be made from a single, continuous sheet or they may be made from separate sheets fused together at the roof-wall interface. The circumferential tube 13 is filled with water to anchor the inflatable enclosure 10 to the decking 14. The inflatable enclosure 10 may be made from any suitable weather-resistant material. For example,

I have employed various vinyl plastics, such as polyvinylacetate and polyvinylchloride.

An inflataable enclosure such as is shown in FIGURE 1 and with which the herein-described invention has utility is fully described in my co-pending application Inflatable Structure, Serial No. 458,609, filed May 25, 1965, (hereafter referred to as my said co-pending application) which is incorporated herein by reference. It will be understood, however, that the foregoing inflatable enclosure is used only by way of example and that this invention may be employed in connection with any enclosure requiring air pressure for support.

The air pressurizing or forced air means comprises, in operable combination, a blower 17, a partially retractable air conduit 18 for conducting air into the inflatable enclosure and a control assembly 19 capable of relating the air pressure within the inflatable enclosure to the amount of air passing from the blower through the air conduit. The blower 17 is of standard construction having a motordriven impeller 20 carried within a housing 21 adjacent an aperture or inlet port 22. Another aperture or outlet port 23 is located in the housing 21 such that air passing in the inlet port 22 passes through the impeller 20 before exiting from the outlet port.

The air conduit 18 comprises a cover portion 24, having a first end (hereafter described as the enclosureremote end) in communication with and preferably larger than the exit port 23 of the blower 17 and having a second end 26 (hereafter described as the enclosure-adjacent end) communicating with the interior of the inflatable enclosure. The cover portion 24 may be formed from any strong, flexible material such as reinforced nylon. The enclosure-remote end 25 is positioned relative to the exit port 23 of the blower 17 such that when the maximum amount of air is required to be flowed into the inflatable enclosure 10, the enclosure-remote end abuts the blower about the exit port. This is preferably accomplished by mounting a portion of the enclosure-remote end 25 to the blower 17 so that the enclosure-remote end can be partially retracted from the blower.

Although the flexible cover portion 24 could be mounted to the blower 17 without reinforcement it is preferable to provide the enclosure-remote end 25 of the air conduit 18 with a reinforcing frame 27 which is mounted on the blower. To this end, the enclosure-remote end 25- of the air conduit 18 is provided with a plurality of open-ended sleeves 28 which are adapted to receive the component members of the frame 27.

The frame 27 comprises two side members 29, a top member 30 and a bottom member 31. The two side members 29 and the bottom member 31 are rigidly interconnected in the general form of a U such that the rigidly interconnected members function as a unit. The upper, unattached ends 32 of the side members 29 of the frame 27 are pivotally mounted on the top member 30 which is a rod sized to be received by aligned openings 33 in the side members 29. The top member 30 is sufliciently long to extend through and beyond the openings 33 in the side members 29 and is threaded at both ends to receive nuts 34 which, when threaded onto the top member, pivotally retain the side members 29 on the top member 30.

In the preferred form of this invention, the top member 30 of the frame 27 is fixedly attached to and supported by the blower housing 21. This is accomplished by passing the top member 30 through aligned openings 36 in a pair of ears 37 projecting from and fixedly attached to the blower housing 21. Nuts (not shown) lock the top member 30 of the frame 27 to the ears 37 on the blower housing 21.

When constructed as described, the U-shaped portion of the frame 27 is capable of being rotated about the stationary top member either into or away from contact with the blower housing 21. The top member 30 of the frame 27 of the air conduit 18 is positioned with respect to the blower housing 21 such that the remote end 25 of the conduit can move into substantially sealing engagement with the blower housing. To aid the remote end 25 of the air conduit 18 to move into sealing engagement with the blower housing 21 a biasing means such as a pair of springs 39 is connected between the bottom member 31 of the frame 27 and the blower housing.

The same result, that is, rotation of the frame 27 away from the blower 17 may be alternatively accomplished by pivotally mounting the top member 30 between the ears 37 extending from the blower and by fixedly attaching the side members 29 to the top member. When mounted in this manner the frame 27 rotates as a unit about the longitudinal axis of the top member 30 which is retained in fixed position relative to the blower 17.

The other or enclosure-adjacent end section 26 of the air conduit 18 flares into a plastic panel 40 which is bonded, for example, by heat scaling, to a section 41 of the wall 16 of the inflatable enclosure 10. The section 41 of the wall 16 and the panel 40 of the air conduit 18 define a passageway 42 having a pair of exit ports 43 opening into the interior of the inflatable enclosure.

The control assembly 19 for relating the volume of air flowing into the inflatable enclosure 10 through the air conduit 18 to the air pressure within the inflatable enclosure, comprises a flexible but substantially nonstretchable cord 44 one end of which is attached to the roof 15 of the inflatable enclosure such as is described in my said co-pending application and a lever 45 one end of which is fixedly attached to a side member 29 of the frame 27. The cord 44 and lever 45 are interconnected at their free ends.

In operation, air is pulled into the blower 17 through the entry port 22 in the blower housing 21 and is expelled through the exit port 23. The blower 17, which is operated continuously, produces a substantially constant volume flow rate of air at the exit port 23 of the blower housing. Substantially all or only a fraction of this air volume exiting from the blower 17 passes into the air conduit 18 depending upon the air pressure within the inflatable enclosure 10.

When there is less air pressure within the inflatable enclosure 10 than is required to provide a sufliciently stable enclosure, the frame 27 of the air conduit 18 is in abutting engagement with the exhaust end of the blower 17 When the air conduit 18 and the blower 17 are in this position, substantially all the air exiting from the exit port 23 of the blower passes into and through the air conduit and flows into the inflatable enclosure 10.

As the air pressure within the inflatable enclosure increases, the roof 15 of the enclosure rises causing the cord 44 to move upwardly. Upward movement of the cord 44 causes the lever 45 to rotate upwardly about its pivot point on the longitudinal axis of the upper member 30 of the conduit frame 27. Since the lever 45 is rigidly connected to the U-shaped unitary portion of the frame 27 which is pivotally carried by the upper member 30 of the frame, the U-shaped portion of the frame rotates upwardly about the upper member. This causes the lower portion of the enclosure-remote end 25 of the air conduit 18 to move away from the blower 17 which, in turn, causes the cover 24 adjacent the U-shaped portion of the frame 27 to retract in accordion fashion, thereby permitting some air to escape into the atmosphere without passing through the air conduit. That is, a portion of the air from the blower 17 is diverted from the enclosure 10.

The amount of air diverted to the atmosphere will depend up the size of the opening between the air conduit 18 and the blower 17. That is, as thi opening increases, a larger percentage of the air exiting from the blower 17 will pass into the atmosphere and a smaller percentage of this air will pass through the air conduit into the inflatable enclosure 10. As the roof 15 of the inflatable enclosure 10 rises to its normal position, the space between the air conduit 18 and the blower 17 gradually increases thereby gradually decreasing the rate of ascent of the roof because of the decreasing amount of air entering the enclosure, and this, in turn, gradually decreases the rate of movement of the bottom portion of the air conduit 18 away from theblower. Thus, it will be understood that the air pressure within the inflatable enclosure and the air exhausted by the blower 17 are interrelated by the control means 19 so that the inflatable enclosure is gradually returned to its normal position thereby eliminating rapid movement of the inflatable enclosure and thereby extending the useful life of the enclosure.

When the inflatable enclosure 10 has been inflated to its normal position, the space between the air conduit 18 and the blower 17 will be at a maximum and the air flowing into the enclosure will be substantially constant and will be equal to the normal leakage of air from the inflatable enclosure.

If air in excess of the normal leakage escapes from the inflatable enclosure 10, the roof of the enclosure lowers thereby lowering the cord 44 which permits the lever 45 and the U-shaped portion of the frame 27 to rotate downwardly about their pivot points on the upper member 30 of the frame. This tends to reduce the space between the air conduit 18 and the blower 17 thereby increasing the air flowing into the inflatable enclosure 10. Thus, as soon as the roof 15 begins to fall, the amount of air passing into the inflatable enclosure 10 immediately increases. Air is continuously introduced into the inflatable enclosure 10 even as the roof lowers to thereby maintain a substantially constant pressure within the enclosure. Therefore, the inflatable enclosure 10 will always be highly stable even in strong winds.

A particular air pressure sensing and transmitting means has ben described. However, it will be understood that other means could be employed to sense pressure changes in an enclosure and to divert air from the blower in accordance with such changes. For example, a weighted flap (not shown) can be cut from the top of the conduit 18 so that three sides of the flap are free and a fourth side, acting as a hinge, remains attached to the conduit. The cord 44 can be attached to a stiffened end of the flap farthest from the hinge end. This combination would operate substantially as previously described. That is, as the inflatable enclosure 10 inflates to maximum pressure, the cord 44 lifts the stiffened end of the flap so that the flap rotates out of contact with the conduit 18 thereby diverting a portion of that amount of air coming from the blower away from the enclosure. A decrease in pressure within the inflatable enclosure is accompanied by a lowering of the cord 44 and a consequent return of the weighted flap to a sealing relation with the conduit 18.

The continuously pressurizing means of this invention may also be used to provide a substantially constant air pressure in non-inflatable buildings, that is, in conventional enclosures. Employed in this way, this invention is the same as described except for the connection means connecting the air conduit 18 to the conventional enclosure and except for the pressure sensing means sensing the pressure within the enclosure. As described, the connection means connecting the air conduit 18 to the inflatable enclosure 10 comprises a panel 40 flaring outwardly from the exit end of the air conduit which is bonded to a section 41 of the wall 16 of the inflatable enclosure 10 to define an airway 42 leading from the air conduit into the interior of the inflatable enclosure. This connecting means is preferably replaced when this invention is employed in conjunction with a conventional enclosure. In its place, it is preferable to provide sleeves in the enclosure-adjacent end 26 of the air conduit 18 similar to the sleeves 28 in the enclosure-remote end 25 of the air conduit and to insert a frame into these sleeves to form a substantially rigid enclosure-adjacent end in the air conduit. This rigid enclosure-adjacent end is then inserted into an aperture in a conventional structure, which aperture substantially conforms in shape and size to the enclosure-adjacent end of the air conduit.

Operation of this invention in conjunction with a conventional enclosure will also vary somewhat from the described operation. In place of the cord 44 which transmits changes in internal air pressure manifested in elevation changes in the roof 15 of the inflated enclosure 10, another means of sensing air pressure and transmitting changes in air pressure to the lever 45 must be used. Conventional pressure sensing and transmitting methods .such as the combination of a diaphragm valve, pressure magnification means and hydraulic linkage may be used.

I have thus described a method and means for providing an enclosure and, particularly an inflatable enclosure, with a substantially constant air pressure. As described, this is accomplished by employing, in combination, a blower which is continuously operated, a retractable conduit and an air pressure sensing and transmitting means which controls the air conduit so that the air conduit accepts varying amounts of air from the blower in response to the air pressure within the enclosure.

Modifications may be made of the herein-described invention by those skilled in the art without departing from the spirit of the invention. Therefore, my invention is to be limited only by the scope of the appended claims.

I claim:

1. A pressurizing device for use in conjunction with inflatable enclosures comprising:

a continuously operating blower having an inlet and an exit port;

an air conduit having a first end communicating with said exit port of said blower and having a second .end communicating with the interior of said inflatable enclosure, said first end being at least partially retractable from said exit port of said blower to vary the air volume passing from said blower into said air conduit;

control means for retracting said first end of said air conduit from said exit port of said blower in relation to the air pressure within said inflatable enclosure comprising (a) retracting means for retracting said first end of said air conduit from said exit port of said blower in response to signals received from (b) pressure transmitting means for sensing and transmitting changes in said air pressure in said inflatable enclosure to said retraction means whereby a substantially constant pressure is maintained in said inflatable enclosure.

2. The device of claim 1 wherein a portion of said first end of said air conduit is mounted on said blower, the remainder of said first end being free to rotate away from said blower.

3. The device of claim 1 wherein said retraction means comprises a lever fixedly attached to said first end of said air conduit.

4. The device of claim 1 wherein said transmitting means comprises a line attached at one end to a portion of the roof of said inflatable enclosure and attached at the other end to said retraction means, said line being flexible but substantially non-stretchable.

5. The device of claim 1 including, in addition, a biasing means for urging said first end of said air conduit into abutting relation with said exit port of said blower.

6. A pressurizing device for use in conjunction with inflatable enclosures comprising:

a blower having an exit port and an inlet port;

a retractable air conduit having a first end communicating with said exit port of said blower and having a second end communicating with the interior of said inflatable enclosure, a portion of said first end mounted on said blower in fixed position relative to said blower and the remaining portion of said first end pivotally mounted on said blower for rotation away from said exit port of said blower;

a lever fixedly attached to said first end of said air conduit for rotating said remaining portion of said first end of said air conduit away from said blower;

a flexible, substantially non-stretchable line afiixed at one end to a portion of the roof of said inflatable enclosure and aflixed at the other end thereof to said lever, said line moving said lever in relation to the air pressure within said inflatable enclosure to control the volume of air passing from said exit port of said blower into said air conduit.

7. The device of claim 6 wherein said device includes biasing means urging said remainder portion of said first end of said air conduit into abutting position with said blower.

8. A pressurizing device for use in conjunction with an inflatable enclosure comprising:

a continuously operating blower having an inlet and an exit port;

an air conduit having a first end communicating with said exit port of said blower and having a second end communicating with the interior of said inflatable enclosure;

diversion means operatively engaged with said air conduit to vary the volume of air passing from said blower into said enclosure in response to changes in pressure within said enclosure; and

pressure sensing means for sensing changes in pressure within said enclosure comprising:

(a) detection means aflixed to the surface of said enclosure for detecting changes in the movement of the surface of said enclosure and '(b) means operatively engaged with said diversion means whereby as the surface of said enclosure moves said diversion means is caused to move to maintain a substantially constant air pressure in said inflatable enclosure.

9. A pressurizing device for use in conjunction with an inflatable enclosure comprising:

a continuously operating blower having an inlet and an exit port;

an air conduit having a first end communicating with said exit port of said blower and having a second end communicating with the interior of said inflatable enclosure, said first end being at least partially retractable from said exit port of said blower to vary the air volume passing from said blower into said air conduit; and

control means for retracting said first end of said air conduit from said exit port of said blower in response to air pressure within said inflatable enclosure.

References Cited UNITED STATES PATENTS 1,985,050 12/1934 Merle 98-15 2,265,461 12/1941 Wagner 98-1.5 3,159,165 4/1961 Cohen 52 2 JOHN E. MURTAGH, Primary Examiner US. Cl. X.R. 522; 98-15 

